1. Field of the Invention
The present invention relates to a silver halide emulsion and to a silver halide photographic light-sensitive material and, more particularly, to a photographic light-sensitive material containing a tabular silver halide emulsion having improved photographic properties and an improved resistance to pressure.
2. Description of the Related Art
In general, various types of pressures are applied onto a photographic light-sensitive material in which a silver halide emulsion is coated. For example, a photographic negative film for a general purpose is bent when it is taken up by a user or loaded in a camera, or pulled upon winding of a frame.
A sheet-like film such as a printing light-sensitive material or a direct medical roentgen light-sensitive material is directly handled by a human hand. Therefore, such a film is often bent.
In addition, all light-sensitive materials are subjected to a high pressure upon cutting or processing.
When various types of pressures are applied on a photographic light-sensitive material as described above, silver halide grains are pressurized via gelatin as a carrier (binder) of the silver halide grains or a plastic film as a support. It is known that photographic properties of a photographic light-sensitive material are changed when a pressure is applied on silver halide grains, and this is reported in detail in, e.g., K. B. Mather, J. Opt. Soc. Am., 38. 1054 (1948). P. Faelens and P.de Smet. Sci. et Ind Phot., 25. No. 5. 178 (1954). P. Faelens. J. Phot. Sci. 2. 105 (1954).
In recent years, a strict demand has arisen for a photographic silver halide emulsion, i.e., a demand has arisen for higher levels of toughness such as storage stability and a resistance to pressure in addition to photographic properties such as sensitivity and image quality, e.g., graininess and sharpness. However, it is obvious that pressure marks are increased as sensitivity is increased. Therefore, a demand has arisen for an emulsion having high sensitivity with less pressure marks. JP-A-63-220228 ("JP-A" means unexamined published Japanese patent application) discloses tabular grains having improved exposure intensity dependency, storage stability, and resistance to pressure. However, pressure marks caused by scratching in a camera or by scratching by a nail are not satisfactorily improved.